A new study shows how eating red meat -- even if it is low in fat and cholesterol -- can still raise the risk of cardiovascular disease. It's down to a chemical called carnitine, which is also found in energy drinks and sold as a dietary supplement.

RFE/RL correspondent Ron Synovitz spoke about the study's findings with Dr. Sarah Jarvis, a general practitioner in London and a clinical consultant for Patient.co.uk, where she writes a regular health and wellness blog. Jarvis has a degree in food and human nutrition from Cambridge University and lectures internationally on the risks of cardiovascular disease and cholesterol.

RFE/RL: U.S. scientists led by Stanley Hazen, a cardiovascular specialist at the Cleveland Clinic in Ohio, have published a new study that suggests it is not just eating fatty red meat that raises the risks of a heart attack or a stroke. Can you explain the significance of this new study?

Sarah Jarvis: We’ve known for a long time that eating too much red meat can undoubtedly be bad for your health. We think that it increases your risk not just of heart disease but also cancer of the bowel.

Now what we are seeing is that, interestingly, it may not simply be the fat in the red meat. It may be a chemical that is found in red meat – in lean red meat, indeed – called carnitine. This carnitine is broken down by the gut and that kicks off a chain of events that can have an ultimate reaction in the body of increasing cholesterol – and particularly, increasing the level of bad cholesterol and reducing the level of good, so-called heart-healthy cholesterol, within the blood. That significantly increases your risk of heart attack or stroke.

Dr. Sarah Jarvis

RFE/RL: How is this discovery going to open up the field of research on the risks of cardiovascular disease?

Jarvis: I don’t think there’s any doubt that having identified that carnitine is broken down in the gut to a gas and that is converted in the liver to a chemical called TMAO – which is linked with the buildup of fatty deposits – we will almost certainly be doing a great deal more in terms of research looking into whether or not [carnitine] is really dangerous in itself.

But interestingly, of course, the positive element of this is this may give scientists some indication of new research as to ways that they might be able to reduce cholesterol and reduce the risk of heart disease.

RFE/RL: So if it is the carnitine in red meat that raises the risk of heart problems, that means people who take dietary supplements containing carnitine also could be at risk of harming themselves.

Jarvis: I’m not remotely surprised to hear this bad news. Unfortunately, as a doctor, I regularly get communication from the medicine and health-care regulatory authority telling me about the health dangers of unregulated diet supplements and energy drinks. I have a real concern that people should not be using unregulated dietary supplements.

It is highly unlikely that you are going to get a safe supplement if you buy one online or you buy one that has not been prescribed by your doctor or recommended by a health-care professional. My advice to all of my patients is that they never, under any circumstances, take any dietary supplement that has not been recommended by their doctor.

RFE/RL: It’s ironic that many people take dietary supplements in the hope of improving their health by reducing their weight.

Jarvis: Unfortunately, with unregulated products such as these carnitine supplements, because they are not regulated the people manufacturing them can essentially make any claim that they want. And I have absolutely no doubt that some people are being sold these completely fraudulently on the basis that they will be guaranteed weight loss. They won’t.

RFE/RL: What about energy drinks? As you mentioned, many of them also contain carnitine.

Jarvis: Of course, the point about energy drinks – they’ve become enormously popular largely because they contain fairly significant amounts of caffeine. If they are also taking a lot of energy drinks which contain chemicals which we don’t know about, and which doctors certainly wouldn’t recommend, they may be putting themselves at risk.